Production of 1,3-alkadienes

ABSTRACT

A 3,6-dihydro-2-(H) pyran, which is substituted with 1 or 2 hydrocarbyl groups in the 3 position or with 1 hydrocarbyl group in the 5 position, is converted, at temperatures in the range of 400*-1,000* F., to a 1,3-alkalidene.

United States Patent Stapp [54] PRODUCTION OF 1,3-ALKADIENES [72] Inventor: Paul R. Stapp, Bartlesville, Okla,

[73] Assignee: Phillips Petroleum Company [22] Filed: Feb. 10, 1970 [21] App1.No.: 10,274

[52] U.S. Cl ..260/68l, 252/455 Z, 260/3451 [51] Int. Cl. ..C07c 1/20, C07c 11/12, C07d 7/00 [58] Field of Search ..260/681, 345.1

[56] References Cited UNITED STATES PATENTS 2,218,640 10/1940 Friedrichsen ..260/681 51 Aug. 1, 1972 2,273,484 2/1942 Guinot ..260/68l 2,387,366 10/1945 Toussaint ..260/681 2,502,431 4/ 1950 Copenhayer et a1 ..260/681 3,280,209 10/ 1966 Tonkyn ..260/681 Primary Examiner-Delbert E. Gantz Assistant Examiner-G. E. Schmitkons Attorney-Young and Quigg 5 7] ABSTRACT 7 Claims, No Drawings PRODUCTION OF 1 ,3-ALKADIENES This invention relates to a process for the production of l,3-alkadienes.

The alkadienes produced by the process of the invention are known in the art and have known utility. For example, l,3-heptadiene can be hydrogenated to normal heptane as in Example ll or can be polymerized according to Chemical Abstracts, Volume 62, column 5,346(a).

Applicant, unexpectedly, has discovered that a 3,6- dihydro-2-[H1pyran which is substituted with l or 2 hydrocarbyl groups in the 3 position or with l hydrocarbyl group in the 5 position yields an alkadiene which is hydrocarbyl-substituted at the 1 position rather than the 2 position. Such a result is truly unexpected as is less stable thermodynamically than Accordingly, it is an object of this invention to provide a process for the production of 1,3-alkadienes.

Other objects, aspects and advantages of this invention will become apparent to one skilled in the art upon consideration of the following disclosure and appended claims.

The conversions of this invention can be represented as follows;

i RCH=CH=CH or H H H OAR wherein R is alkyl, cycloalkyl, aryl or combinations thereof such as alkylaryl, arylalkyl, and the like having from one to carbon atoms per R group and wherein R is R or hydrogen.

Specific examples of hydrocarbyl-substituted 3,6- dihydro-2-[H]pyrans that can be employed in the process of this invention are: 3-propyl-3,6-dihydro-2- [H]pyran, 5propyl-3,6-dihydro-2-[H]pyran, 3-methyl- 3,6-dihydro-2-[H]pyran, 3-decyl-3,6-dihydro-2- [H]pyran, 3,3-dimethyl-3,6-dihydro-2-[H]pyran, 3,3- didecyl-3,6-dihydro-2-[H]pyran, 3-cyclopentyl-3,6- dihydro-2-[H]pyran, 3-cyclodecyl-3,6-dihydro-2- [H ]pyran, 3-phenyl-3,6-dihydro-2-[H]pyran, 3-benzyl- 3,6-dihydro-2-[H]pyran, 3-(2-naphthyl)-3,6-dihydro- 2-[H]pyran, 3-(4-phenylbutyl)-3,6-dihydro-2-[H] pyran, 3-(4-butylphenyl)-3,6-dihydro-2-[H]pyran, 3- (3-methylphenyl)-3,6-dihydro-2-[H]pyran, 3-( 3-butylcyclohexyl)-3,6-dihydro-2-[l-l]pyran, 3-(4-cyclohexyl- 2 butyl)-3,6-dihydro-2-[H]pyran, 3-decyl-3-(4- methylphenyl)-3,6-dihydro-2-[H]pyran, 3-(4-butylcyclohexyl)-3-methyl-3,6-dihydro- 2-[l-llpyran, (2,2,3-trimethylheptyl)-3-phenyl-3,6-dihydro-2-[ Hlpyran, 3-cyclopentyl-3-ethyl-3,6-dihydro-2-[H] pyran, 5-methyl-3,6-dihydro-2-[l-l]pyran, 5-decyl-3,6- dihydro-2-[5pyran, 5-cyclopentyl-3,6-dihydro-2- [l-l]pyran, 5-cyclodecyl-3,6-dihydro-2-[H]pyran, 5- phenyl-3,6-dihydro-2-[H]pyran, 5-benzyl-3,6-dihydro- 2-[H]pyran, 5-(2-naphthyl)-3,6-dihydro-2-[H]pyran, 5-(4-phenylbutyl)-3,6-dihydro-2-[H]pyran, 5-(4-butylphenyl)-3,6-dihydro-2-[H]pyran, 5-(3-methylphenyl)-3,6-dihydro-2-[H]pyran, 5-( 3-butylcyclohexyl)-3,6 -dihydro-2-[H]pyran, 5-(4-cyclohexyl-butyl)-3,6- dihydro-2-[H]pyran, and the like.

The 3,6-dihydro-2-[H1pyrans employed in this invention can be produced by any means known in the art. For example, they can be produced by the process described in co-pending application Ser. No. 678,519 filed on Oct. 27, 1967, now United States Letters Patent 3,527,771 issued September 8, 1970.

Specific examples of 1,3-alkadienes that can be produced by the process of this invention are: l,3-heptadiene, 1,3-pentadiene, l,3-tetradecadiene, 4-methyll ,3-pentadiene, 4-decyll ,3-tetradecadiene, lcyclopentyl-l ,3-butadiene, l-cyclodecyll ,3-butadiene, l -phenyll ,3-butadiene, S-phenyll ,3-pentadiene, l-(2-naphthyl)- l ,S-butadiene, 8-phenyl-l ,3- octadiene, l-(4-butylphenyl)-1,3-butadiene, l-(3- methylphenyl)- 1 ,3-butadiene, l-( 3-butylcyclohexyl)- 1 ,3-butadiene, 8-cyclohexyl-1,3-octadiene, 4-(4- methyl-phenyl)tetradecadiene, 4-(4-butylcyclohexyl)- l,3-pentadiene, '4-phenyl-6,6,7-tiimethyl-l,3 undecadiene, 4-cyclopentyl-1,3-hexadiene, and the like.

Generally, the reaction temperature ranges from 400l000 F preferably from 650850 F. Pressures can be in the range of 0.5 to 10 atmospheres. Reaction times sufiicient to carry out the desired degree of conversion are employed. Generally, the contact time ranges from 0.1 seconds to 60 minutes, preferably 0.1 seconds to 10 minutes. The contact normally is carried out in the vapor phase.

A catalyst such as alumina, silica, zeolite, boria, zirconia, zinc spinels, titania, and the like, or mixtures thereof is employed. The preferred catalyst is alumina.

The advantages of this invention are further illustrated by the following examples. The reactants and proportions and other specific conditions are presented as being typical and should not be construed to limit the invention unduly.

EXAMPLE I A solution comprised of 495 g (420 g, 7.5 moles KOH) of percent KOH aqueous solution in 1.5 liters of ethylene glycol and 505 g (3.2 moles) of 3-propyl-4- chlorotetrahydropyran was charged to a reactor, refluxed, and stirred for 12 hours. The reaction mixture upon cooling was diluted with water and extracted with ether. The ether solution was dried with magnesium sulfate and filtered. The ether was removed from the filtrate and the residue was fractionated to yield 398.7 g of a mixture comprised of 3-propyl-3,6-dihydro-2- [H]pyran and 5-propyl-3,6-dihydro-2-[H]pyran in a 1:2 mole ratio which constituted a yield of 99.5 mole percent based on the 3-propyl-4- EXAMPLE II A stainless steel reactor was charged with 40 g of 8-14 mesh Alcoa F -l alumina and was heated to a temperature of 700-750 F. while a total of 78 g (0.62 moles) of the mixture of 3-propyl-3,6-dihydro-2- [H]pyran and -propyl-3,6-dihydro-2-[H1pyran was passed through the reactor over a period of 45 minutes. The product was collected in a dry ice acetone trap and subsequently analyzed by gas liquid chromatography. It was determined that there was an 84 mole percent conversion. A 64 mole percent yield based on the propyl dihydropyrans charged was determined to have been produced. The 1,3-heptadiene product which was recovered was determined to have a carbon content of 86.4 percent, a hydrogen content of 13.2 percent, and a molecular weight of 93 as compared to the theoretical expected carbon content of 87.5 percent, hydrogen content of 12.5 percent, and molecular weight of 96. This run clearly demonstrates that the desired 1,3-alkadienes are produced in substantial amounts by the process of this invention.

Ten ml of the 1,3-heptadiene product produced above in 50 ml of 95 weight percent aqueous ethanol solution was hydrogenated over platinum at 50 psig hydrogen in a Parr apparatus for about 16 hours. The product was filtered, diluted with water, and extracted with pentane. The pentane extracts were washed with water, dried with magnesium sulfate, filtered, and analyzed by capillary gas-liquid chromatography. The hydrogenated product was determined to be 81 percent (mole) normal heptane.

Although this invention has been described in considerable detail, it must be understood that such detail is for the purpose of illustration only and that many variations and modifications can be made by one skilled in the art without departing from the scope and the spirit thereof.

I claim:

1. A process for the production of at least one alkadiene represented by the fonnula comprising heating at least one hydrocarbyl substituted 3,6-dihydro-2-db[H]-pyran represented by the formula n HAOH group and R is R or hydrogen.

2. A process according to claim 1 wherein said heatin g is carried out at a temperature ranging from 650 to 850 F., for a time ranging from 0.1 seconds to 60 minutes and at a pressure ranging from 0.5 to 10 atmospheres.

3. A process according to claim 1 wherein said catalyst is alumina.

4. A process according to claim 1 wherein the amount of catalyst ranges from 0.0001 to 10 g per 1 g of 3,6-dihydro-2-[H]pyran.

5. A process according to claim 1 wherein the amount of catalyst ranges from 0.01 to 5 g per 1 g of 3,6-dihydro-2-[Hlpyran 6. A process according to claim 1 wherein said 3,6- dihydro-2-[H]pyran is 3-propyl-3,6-dihydro-2- [Hlpyran or 5-propyl-3,6-dihydro-2-[l-lpyran or mixtures thereof.

7. A process according to claim 1 wherein said alkadiene is 1,3-heptadiene.

UNITED, STATES PATENT OFFVICE CERTIFICATE OF CORRECTION Patent Nou 3,681, +71 Paul R. Stapp Dated August 1, 1972 It is certified that errorappears in the above-identified patent and that Letters Patent are hereby corrected as shown below:

IN THE ABSTRACT Line 5, "alkalidene" should read alkadiene IN THE CLAIMS Claim 1, column h, line 10, "3,6-dih aro-2-db[H]- ran" should read 3,6-dihydro-2-[H1-pyran Y Claim 6; column 4, line MO, "5-propyl-3,6-dihydro-2-[Hpyra.n" should read 5-propyl-3,6-dihydro-2-[H1pyran Signed and sealed this 2nd day of January 1973..

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents 

2. A process according to claim 1 wherein said heating is carried out at a temperature ranging from 650* to 850* F., for a time ranging from 0.1 seconds to 60 minutes and at a pressure ranging from 0.5 to 10 atmospheres.
 3. A process according to claim 1 wherein said catalyst is alumina.
 4. A process according to claim 1 wherein the amount of catalyst ranges from 0.0001 to 10 g per 1 g of 3,6-dihydro-2-(H)pyran.
 5. A process according to claim 1 wherein the amount of catalyst ranges from 0.01 to 5 g per 1 g of 3,6-dihydro-2-(H)pyran.
 6. A process according to claim 1 wherein said 3,6-dihydro-2-(H)pyran is 3-propyl-3,6-dihydro-2-(H)pyran or 5-propyl-3,6-dihydro-2-(Hpyran or mixtures thereof.
 7. A process according to claim 1 wherein said alkadiene is 1,3-heptadiene. 